This invention relates to an automobile door locking/unlocking, ignition switching-engine starting, and burglar alarm system, which does not require a mechanical key. This system is intended to free a person from the nuisances of (1) carrying an automobile key always, (2) locking himself outside the automobile with the key inside, and (3) sometimes finding his automobile stolen.
For the driver, the system provides convenience and safety of a centralized operation of locking and unlocking doors and trunk while the automobile is parked or being driven.
The system consists of code sensing circuit, locking/unlocking control logic, solenoid/ignition switching circuit and illogical status detecting alarm circuit. The code sensing circuit recognizes the driver's own password by means of either push-button or optically-coded card; and the locking/unlocking control logic generates, memorizes locking or unlocking signals. The solenoid/ignition switching circuit actually controls the automobile systems; and the illogical status detecting alarm circuit generates burglar warning signals.
The usual automobile uses a mechanical key to lock and unlock doors and to turn on and off the electric power to accessory apparatus, ignition coils and starting motor. Therefore, the driver must always carry the key with him or her. In modern busy life, carrying a key is sometimes troublesome for people. Everyone will be delighted if he can be free from carrying a key, so that he is forever free from the agony of losing the key.
Furthermore, one can't easily avoid the difficult situation of locking doors with the key left inside of the automobile. Also the mechanical key is vulnerable to burglars who can open doors by similar keys. Most automobile losses are because of this reason; and this is not only a property loss for individuals involved, but also results in crime increase which is now becoming a serious social problem.
The main object of this invention is to do away with this key. When this invention is employed, instead of a key, a push button pad or driver's license or some other card with a barcode or optical code on the back side of it is used.
When the driver, from the outside of an auto, pushes a certai combination of numbers on the push button pad or passes an opticalcode card through a sensor, the digital circuitry identifies this code and compares it to the preset code in the instrument. When the two codes match with each other, the unlocking pulse is generated which drives the switching transistor and in turn, energizes front door solenoids toward door unlocking position. At the same time, the unlocking pulse is stored in the latch (memory) circuit for an unlocking status and it enables the car battery voltage to be applied to automobile electric systems including the ignition coil and starting motor by the use of power switch.
When the locking button (one to four buttons could be pressed simultaneously to lock all doors) is pressed, the locking pulse drives a switching transistor and energizes all door solenoids toward door locking position. Thereafter, the latch circuit is memorized as locking status; and in this status, no battery power is applied either to the electric system or ignition and starting motor. Nobody can then open a door and get in the automobile.
Even if one gets in the auto in some irregular way, he is unable to turn on the power switch unless he knows the code. Thus, it is impossible for him or her to drive the car, since the locking status of the latch circuit cuts off the battery power line.
There are also an internal door lock/unlock switch and a trunk open switch on the front panel of the auto; and these switches can be conveniently used for locking and unlocking of all doors as well as opening trunk from the front seats. Although these features are not new for many existing expensive cars, it is an advantage of this system to enable these two functions simultaneously.
Either a rotary switch or a push button could be used for the main power switch which replaces the regular key-operated ignition switch. In case of rotary switch option, there are five switching positions, LOCK-OFF-ACCESSORY ON-RUN-START. If one rotates the power rotary switch to "lock" position, the system will be reset to lock status which disables battery power switching without locking doors. On the other hand, in case of push button option, there are two buttons and a switch. One button is the power button which provides the battery power switching status: OFF.fwdarw.ACCESSORY ON.fwdarw.RUN.fwdarw.ACCESSORY ON.fwdarw.OFF (repeated in the same order) as the button is pushed repeatedly. There is separate "start" switch, which turns the starting motor on and off when the POWER button is in the RUN status. The "lock" button shuts off the power switching without locking doors.
By the functions described up to now, this system could protect against almost all automobile thefts. However, if the thief is a very electrically-intellectual person who knows automobile electrical systems well, he will disconnect this system wiring and connect a wire from the auto battery terminal directly to the ignition circuit, and also jumpers to the starting motor to fire the engine. This rare possibility could also be prohibited by the burglar alarm circuit, which turns electric horns on and off if any power voltage is applied to the ignition coil during the locking status of the latch circuit.
The pass number (cipher combination) reading device can be either a four push button set, or a magnetic code or optical code reader, installed in left and right front doors. When a magnetic or bar code reader is used, a magnetic tape or optical code label which is coded to a specific pass number should be attached to the back side of a drivers license, or of other card like commercial credit card. This will also prevent drivers from travelling without a driver's license. When using four hexadecimal digits, as in the example schematic diagram, the system has 65535 (16.times.16.times.16.times.16-1) combinations for coding.